FIELD OF THE INVENTION
This invention relates to a tubular fuel rail for supplying fuel to a plurality of electromagnetic fuel injectors for a multicylinder internal combustion engine. More specifically it relates to a fuel rail having a plurality of spaced apart bulbous or nodular sections defining fuel sumps which surround recessed sockets for containing end portions of the injectors and supplying fuel thereto.
Prior art fuel rails may have functioned acceptably but many were made up of a large number of separate parts. The large number of parts resulted in unnecessary manufacturing costs and difficulties, particularly in placing the parts in their relative positions and integrally connecting and sealing the parts together. Some of the early fuel rails were bulky and interferred with access to the injectors or to adjacent parts. Occasionally audible noise would develop as a result of a resonant interaction caused by the timed movement of fuel into the injectors. Another problem which may be related to resonance was that injector outputs varied depending upon the location of the injector. Apparently turbulence or some other unexplained internal factor affected the distribution of fuel to the separate injector sites and caused this lack of uniformity. In some prior art fuel rails the fuel inlets to the sockets were located at the lowest level of the fuel rail and thus water and dirt contaminents in the fuel could easily gravitate directly into the fuel inlets and be inducted into the injectors. In addition most of the prior art fuel rails supplied fuel to the tops of the injectors. This condition required the fuel rails to be positioned over the tops of the injectors and thus be mounted a substantial distance away from the engine's intake manifold. Such positioning was less than ideal. For one thing it required the use of strong fuel rails and strong supporting brackets in order to withstand the constant vibration and other large moments of force incident with the operation of a motor vehicle. Another problem with such fuel delivery systems was that they occupied too much space. Furthermore, if one of the injectors failed in use, the entire fuel rail had to be removed in order to gain access to the faulty injector.
Accordingly it is a general object of this invention to solve the aforementioned problems and to do so with a fuel rail assembly that effectively supplies fuel to the injectors, is also compact, durable, economical and easy to manufacture utilizing high production output machinery. The invention disclosed herein solves a number of these problems by forming the injector sockets directly in the top or bottom half of the fuel rail. The sockets are recessed into the rail rather than projecting below or above it. This allows for a reduction in the height of the rail. The bulbous sump chamber sections appear to dampen or attenuate noise impulses produced by the pulsed flow of fuel into the injectors. The combination of bulbous sump sections connected by narrow tubular arteries appears to prevent resonant noise buildup from one sump to another. This combination also provides a marked improvement to injector output uniformity. Fuel is fed into the injector sockets through inlets located above the bottom of the sump chambers so that fuel contaminants which may enter the rail cannot gravitate into the socket inlets.